1. Field of the Invention
The present invention relates to electronic packaging in general and, in particular, to electronic packaging of Personal Computers (PC) and other network interconnecting devices.
2. Prior Art
Personal computers and network interconnecting devices such as routers, concentrators, etc. typically have an enclosure in which several components are mounted. Typical components include blowers, hard disk, motherboard, circuit cards, etc. Most of the designs were roll-your-own in that each manufacturer designs its machines to its own liking without regard for interchangeability of parts from other manufacturers. Examples of prior art machines are set forth in U.S. Pat. Nos. 4,916,578; 5,175,669; 5,218,514; 5,519,573; 5,596,483 and 5,600,538.
U.S. Pat. No. 4,916,578 (Personal Computer Chassis Connection Method). This patent shows a box that uses a sliding 4-sided top cover over a 3-sided base with a special interlock detail for EMC sealing. The adapters are vertically oriented and top pluggable, requiring removal of the top cover first. The corner EMC seal is a contact clip.
U.S. Pat. No. 5,175,669 (Support Member that Couples an Electronic Card to a Chassis). This patent shows a mechanism for retaining an adapter card which is installed into a box from the top. The top cover would have to be removed to access the adapter. The mechanism would probably be molded plastic so that it can flex to snap into the retaining slots in the box base. The adapters plug into a mother board and are oriented vertically in the box.
U.S. Pat. No. 5,218,514 (Compact High Power Personal Computer with Improved Air Cooling System). This patent describes a cooling system for a personal computer box that pulls air in through apertures in the front and blows it out the back. It also describes the location of the components within the box such as the power supply and riser board and I/O cards which are horizontally oriented. The patent seems very specific to the product it describes.
U.S. Pat. No. 5,519,573 (I/O Riser Card for Motherboard in Personal Computer/Server). This patent shows a mother board with a vertically oriented riser board for I/O connection attached. The riser board has an EMC gasket (40) mentioned. The description is a compliant die-cut part which has connector exit openings and is sandwiched between the outer box case.
U.S. Pat. No. 5,596,483 (Silent Air Cooled Computer . . . ). This patent claims a very specific means for cooling a hard drive which apparently also reduces noise levels. It claims a fan which is adhesively mounted to an elastic gasket. It also claims a hard drive with a fluid containing pouch.
U.S. Pat. No. 5,600,538 (Personal Computer and Housing Structure . . . ). This patent describes an Apple computer with removable decorative panels and with a removable mother board with a sub-chassis mounted on top. The disk drives are mounted on slides which are accessible from the front exterior of the box after a decorative panel is removed. The patent appears very specific to the Apple product.
There seems to be a trend, in the computer and communications industries, toward open systems whereby hardware would be compatible with other hardware no matter what company makes it. To foster this interchangeability, several companies have formed a consortium called PCI Industrial Computer Manufacturers Group (PICMG.TM.) which promulgates the CompactPCI.RTM. (Peripheral Component Interconnect) specification that uses industry standard mechanical components and high performance connector technologies to provide a system intended for rugged environments. Included in the specification is a standard form factor for adapters or boards. Both 3U (100 mm by 160 mm) and 6U (233.35 mm by 160 mm) board size are defined. More details are set forth in the standard which is incorporated herein by reference.
Even though the specification is a step in the right direction in that electronics are packaged on a standardized board that fits enclosures from different manufacturers, the enclosures themselves are built on a "roll-your-own" interchangeable component design. Kits containing mechanical parts for the enclosures can be purchased and assembled. The enclosures are usually expensive due to high cost for the mechanical components and labor costs for manually assembling them. In addition, the fit between parts are variable due to tolerances and to variable assembly positions. Moreover, the appearances are not pleasing; thus, requiring covers that further augment the overall cost. Finally, these "tinker-toy like" enclosures are not very good in providing EMI shielding.